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dhcpd: apparently, sometimes IP is in ciaddr, not requested_ip...

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also revert the part which appempted to "fix" that in client

function                                             old     new   delta
udhcpd_main                                         1949    1964     +15
send_renew                                           142     105     -37
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 15/-37)            Total: -22 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-03-21 06:46:09 +01:00
parent c7dc79e71d
commit 53f72bb3f0
2 changed files with 92 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
networking/udhcp/clientpacket.c
View File

@ -156,20 +156,7 @@ int FAST_FUNC send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
init_packet(&packet, DHCPREQUEST);
packet.xid = xid;
/* RFC 2131:
* "3.2 Client-server interaction - reusing a previously
* allocated network address"...
* The client broadcasts a DHCPREQUEST message on its local subnet.
* The message includes the client's network address in the
* REQUESTED_IP option. As the client has not received its
* network address, it MUST NOT fill in the 'ciaddr' field."
*
* FIXME: we seem to not follow this, we do set ciaddr.
*/
packet.ciaddr = ciaddr;
add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr);
if (server)
add_simple_option(packet.options, DHCP_SERVER_ID, server);
add_param_req_option(&packet);
bb_info_msg("Sending renew...");

99
networking/udhcp/dhcpd.c
View File

@ -48,7 +48,7 @@ static void send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadc
if (force_broadcast
|| (dhcp_pkt->flags & htons(BROADCAST_FLAG))
|| !dhcp_pkt->ciaddr
|| dhcp_pkt->ciaddr == 0
) {
log1("Broadcasting packet to client");
ciaddr = INADDR_BROADCAST;
@ -466,16 +466,101 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
case DHCPREQUEST:
log1("Received REQUEST");
/* RFC 2131:
/* RFC 2131: "The REQUESTED_IP option MUST be set
* to the value of 'yiaddr' in the DHCPOFFER message
* from the server." */
o DHCPREQUEST generated during SELECTING state:
Client inserts the address of the selected server in 'server
identifier', 'ciaddr' MUST be zero, 'requested IP address' MUST be
filled in with the yiaddr value from the chosen DHCPOFFER.
Note that the client may choose to collect several DHCPOFFER
messages and select the "best" offer. The client indicates its
selection by identifying the offering server in the DHCPREQUEST
message. If the client receives no acceptable offers, the client
may choose to try another DHCPDISCOVER message. Therefore, the
servers may not receive a specific DHCPREQUEST from which they can
decide whether or not the client has accepted the offer.
o DHCPREQUEST generated during INIT-REBOOT state:
'server identifier' MUST NOT be filled in, 'requested IP address'
option MUST be filled in with client's notion of its previously
assigned address. 'ciaddr' MUST be zero. The client is seeking to
verify a previously allocated, cached configuration. Server SHOULD
send a DHCPNAK message to the client if the 'requested IP address'
is incorrect, or is on the wrong network.
Determining whether a client in the INIT-REBOOT state is on the
correct network is done by examining the contents of 'giaddr', the
'requested IP address' option, and a database lookup. If the DHCP
server detects that the client is on the wrong net (i.e., the
result of applying the local subnet mask or remote subnet mask (if
'giaddr' is not zero) to 'requested IP address' option value
doesn't match reality), then the server SHOULD send a DHCPNAK
message to the client.
If the network is correct, then the DHCP server should check if
the client's notion of its IP address is correct. If not, then the
server SHOULD send a DHCPNAK message to the client. If the DHCP
server has no record of this client, then it MUST remain silent,
and MAY output a warning to the network administrator. This
behavior is necessary for peaceful coexistence of non-
communicating DHCP servers on the same wire.
If 'giaddr' is 0x0 in the DHCPREQUEST message, the client is on
the same subnet as the server. The server MUST broadcast the
DHCPNAK message to the 0xffffffff broadcast address because the
client may not have a correct network address or subnet mask, and
the client may not be answering ARP requests.
If 'giaddr' is set in the DHCPREQUEST message, the client is on a
different subnet. The server MUST set the broadcast bit in the
DHCPNAK, so that the relay agent will broadcast the DHCPNAK to the
client, because the client may not have a correct network address
or subnet mask, and the client may not be answering ARP requests.
o DHCPREQUEST generated during RENEWING state:
'server identifier' MUST NOT be filled in, 'requested IP address'
option MUST NOT be filled in, 'ciaddr' MUST be filled in with
client's IP address. In this situation, the client is completely
configured, and is trying to extend its lease. This message will
be unicast, so no relay agents will be involved in its
transmission. Because 'giaddr' is therefore not filled in, the
DHCP server will trust the value in 'ciaddr', and use it when
replying to the client.
A client MAY choose to renew or extend its lease prior to T1. The
server may choose not to extend the lease (as a policy decision by
the network administrator), but should return a DHCPACK message
regardless.
o DHCPREQUEST generated during REBINDING state:
'server identifier' MUST NOT be filled in, 'requested IP address'
option MUST NOT be filled in, 'ciaddr' MUST be filled in with
client's IP address. In this situation, the client is completely
configured, and is trying to extend its lease. This message MUST
be broadcast to the 0xffffffff IP broadcast address. The DHCP
server SHOULD check 'ciaddr' for correctness before replying to
the DHCPREQUEST.
The DHCPREQUEST from a REBINDING client is intended to accommodate
sites that have multiple DHCP servers and a mechanism for
maintaining consistency among leases managed by multiple servers.
A DHCP server MAY extend a client's lease only if it has local
administrative authority to do so.
*/
if (!requested_opt) {
log1("no requested IP, ignoring");
break;
requested_nip = packet.ciaddr;
if (requested_nip == 0) {
log1("no requested IP and no ciaddr, ignoring");
break;
}
}
if (lease && requested_nip == lease->lease_nip) {
/* client requests IP which matches the lease.
/* client requested or configured IP matches the lease.
* ACK it, and bump lease expiration time. */
send_ACK(&packet, lease->lease_nip);
break;